The impact of a deep vertical medical alliance on enhancing clinical capacity and reversing patient outflow at a Chinese county hospital: a 4-year case study.

Introduction: County hospitals form the backbone of the rural healthcare delivery system in China, yet they frequently suffer from "patient drain". This behavior exacerbates regional health disparities and undermines the tiered healthcare model. While vertical integration strategies, such as Medical Alliances, have been proposed as a solution, evidence regarding their efficacy-particularly for deep, governance-oriented integration models- remains fragmented. This study aims to evaluate the impact of a "Deep Vertical Integration" strategy on the clinical capacity, operational efficiency, and regional patient flow dynamics of a county-level hospital. Methods: The setting was Sui Ning County People's Hospital (SNCPH), which formed a deep alliance with a tertiary academic center, The Affiliated Hospital of Xuzhou Medical University (AHXMU). We employed a single-case, quasi-experimental Interrupted Time Series (ITS) design spanning 48 months (January 2021-December 2024), utilizing 72 months of longitudinal administrative data (including pre-intervention baselines) to control secular trends and seasonality. The intervention followed a "Three-Dimensional Strategy": (1) Governance Restructuring (embedded executive leadership and shared financial mechanisms); (2) Technological Empowerment (standardized surgical training and graded authorization); (3) Operational Optimization (DRG-based cost control and AI-assisted quality management). Outcomes were measured using patient-level referral data, surgical complexity grading (Grade IV ratio), and financial structure metrics. Results: The implementation of deep vertical integration was associated with substantial improvements in hospital performance. The proportion of Grade IV surgeries (complex/critical procedures) increased significantly to 20.0% of all surgical cases by 2024 (P < 0.001), indicating a measurable upgrade in local technical capacity. Concurrently, the model successfully reversed patient outflow: outward referrals to tertiary centers decreased by 64.8% (95% CI [62.1%, 67.5%]), dropping from 1,073 in 2021 to a projected 378 in 2024. ITS analysis confirmed a statistically significant change in the post-intervention trend for patient outflow (P < 0.001) that was robust to autocorrelation testing. Financially, the hospital achieved structural optimization, with medical service revenue increasing by 7.41 percentage points, signaling a shift from drug-reliant to value-based revenue models. Discussion: Deep vertical integration, characterized by embedded governance and standardized technical mentorship, offers a potent mechanism for strengthening county-level healthcare.